Sterilize 5 1-pint canning jars, lids, and rings in boiling water. Meanwhile, combine the wine, sugar, vinegar, and salt in large saucepan and bring to a boil, then hold at 180°F. Remove jars from boiling water, and pack the Mandarin segments in the warm jars. Add 1 tablespoon of peppercorns to each jar, and fill the jars with hot aigre-doux liquid, leaving ½ inch of space at the top of the jar.
Remove the lids and rings from the boiling water, and seal the jars. Process the jars in a boiling water canner, covered by 1 inch of water, for 15 minutes—begin the processing time when the water comes to a boil. At the end of the processing time, remove the jars, check to make sure the lids are sealed, and cool the jars away from drafts.
Store the sealed jars in a cool, dry location. Check the pH of each batch within 24 hours; foods at a pH of 4.6 or lower are safe. Let the Mandarins cure for at least 1 week and up to 1 year.